Dark Kleintenrek
| Dark Kleintenrek | ||||||||||||
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| Microgale jobihely | ||||||||||||
| Goodman , Raxworthy , Maminirina & Olson , 2006 |
The Dunkle Kleintenrek ( Microgale jobihely ), also Nördlicher Kleintenrek or Nördlicher Kleintanrek , is a species of mammal from the genus Kleintenreks within the Tenrek family . It occurs with two separate populations in northern and central-eastern Madagascar . The animal habitat includes wooded mountainous areas. The species is a medium-sized representative of the Kleintenreks, it is characterized by a strong body with agouti-like fur, an elongated head with a narrow snout and a tail that is only slightly shorter than the rest of the body. The animals are likely to live on the ground, but little is known about their way of life. The first scientific description of the species took place in 2006. Its population is seriously threatened.
features
Habitus
The Dunkle Kleintenrek is one of the medium-sized representatives of the Kleintenreks. Its head-torso length is 5.3 to 6.2 cm, the tail is 4.5 to 5.7 cm long, which is only slightly shorter than the rest of the body. The body weight is 8 to 10 g. In terms of physique, the Dark Kleintenrek corresponds to its fellow species. The body appears spindle-shaped, the legs are short and strong and the head is elongated and pointed at the front. The back fur shows a mixture of completely black and dark red-brown hair roughly from the base of the ears to the root of the tail and including the sides, creating an agouti- like fur pattern. Individual guide hairs are dark brown and 5 to 6 mm long. The underside has a finer textured fur that is a little lighter in color. The agouti pattern is created here by a mixture of dull brown to gray-brown hair, the bases of which appear medium gray. On the sides there is more of a smooth transition from the drawing on the top to the bottom. The ears are comparatively short with a length of 13 to 14 mm. The auricle consists of dark brown skin, which is covered inside and outside with equally colored hair. The vibrissae are black, they are 15 mm long at the snout and 5 mm long at the nose. The tail has a dark brown skin on top and pale brown skin on the underside. The fine fur that covers the tail is more black on the back and more reddish brown on the underside. The front and rear feet each have five rays. The top of the feet is covered with dark brown fur, and small tufts of hair protrude over the claws on the hind feet. The total length of the rear foot is 12 to 13 mm, which is also relatively short. The inner beam of the rear foot reaches less than a third of the length of the second, laterally adjacent, beam, while the outer beam is two thirds of the length of the fourth. The three inner rays (II to IV) are almost equally long.
Skull and dentition features
The skull becomes 20 to 20.6 mm long and 9.2 mm wide at the cranium. Overall, it appears rather short and somewhat flattened on the sides. The rostrum is rather short and narrow, but the nasal bones are elongated. There is a slight lateral constriction of the skull behind the eyes. The frontal bone bulges slightly, the bulge on the occiput appears weak. The zygomatic arches are not closed. The lower jaw is slim and has a short and narrow angular process, the crown process points backwards. At the base of the skull there is a weakly indented glenoid pit connecting with the mandibular joint.
The teeth structure similar to that of other microgale, the dental formula is: . The rows of teeth run roughly parallel to each other in the middle and rear section and converge slightly towards the front. Overall, the bit doesn't look very robust. In the upper row of teeth, there are smaller gaps between the first two incisors and between the canine and the anterior premolar ; there are no conspicuous diastemas in the lower jaw . The upper inner incisor is enlarged and two-humped ( bicuspid ), the second incisor only reaches half the height of the first, but is three-humped ( tricuspid ). The last, only unicuspid, incisor is the smallest, while the canine is almost as high as the second. In the lower jaw, the first two incisors and the canine are almost the same size. The molars show a typical zalambdodont chewing surface pattern with three distinctive cusps. The last two premolars in the upper dentition are very large, the last one is larger than the molars that follow. the last upper molar is greatly reduced in size. In the lower dentition, the last premolar and the three molars are similar in size. The total length of the upper row of teeth is 9.2 to 9.6 mm.
distribution
The dark little tenrek occurs with two clearly separated populations in the northern and central-eastern part of Madagascar . In the north it is documented on the basis of twelve individuals from two sites on the south-western slopes of the Tsaratanana massif in the province of Mahajanga . The sites are located at altitudes of 1420 to 1680 m. The region consists of mountain forests with trees up to 15 m high, but the canopy is not completely closed. Numerous lianas are typical , the ground is covered by a sparse layer of herbs and interspersed with rotting tree trunks. The two sites, the Forêt du lac Matsiborimena on the one hand and the Forêt d'Analapakila on the other , are only 12 km apart. Since the area provided the first record of the species, the Dunkle Kleintenrek was initially considered to be one of the few representatives of the genus with a more restricted distribution area. The cause was considered to be the steeper structure and greater geographical isolation of the Tsaratanana massif, which also includes the island's highest mountain, the Maromokotro . In contrast, the central highlands of Madagascar are more closely connected and less rugged. In 2010, a further population of the dark small tenrec was reported in the Forêt d'Ambatovy-Analamay around 485 km southeast of the Tsaratanana massif in the Toamasina province . There six individuals could be observed at three localities between 1000 and 1110 m above sea level, the sites are spread over an area of 0.43 km². While both populations are outwardly similar, the animals in eastern Madagascar are on average slightly larger (total length 12.2 to 13.1 cm) and slightly heavier (weight 8.5 to 10 g), have a slightly shorter tail and show individual morphometric deviations in relation to the skull and dentition features compared to their relatives from the north. The sites are in dense, moist forests with open undergrowth, but the soil is ultra-basic , which is due to the presence of nickel and cobalt . The Dunkle Kleintenrek appears here sympathetically with various other Kleintenreks, such as the Cowan-Kleintenrek ( Microgale cowani ), the Thomas-Kleintenrek ( Microgale thomasi ) or the Little Long-tailed Kleintenrek ( Microgale longicaudata ). The extent of the total distribution area is given as 282 km², provided that there are more between the two isolated stands, this could be a maximum of 9000 km².
Way of life
The way of life of the dark little tenrec has hardly been researched. All previously known individuals have been observed on the ground, so the species most likely lives terrestrially. This is also indicated by the structure of the feet with their rays II to IV, which are almost the same length. The animals of the Tsaratanana massif were captured in a very short period of about a week in March 2003, they represent different age groups including a milk-producing female. This suggests that reproduction is probably not dependent on the season.
Systematics
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Internal systematics of the Kleintenreks according to Everson et al. 2016
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The Dark Kleintenrek is a kind from the genus of microgale ( Microgale ) within the family of tenrecs (Tenrecidae). The Kleintenreks together with the rice burrowers ( Oryzorictes ) and the representatives of the genus Nesogale make up the subfamily of the Reistenreks (Oryzorictinae). So far, more than 20 species of Kleintenreks are known, making them the most diverse member of the family. Due to some morphological features, they are considered to be more originally within the Tenreks. The genus was formed in the Lower Miocene around 16.8 million years ago, and it diversified very strongly in the period that followed. Today's representatives are adapted to different ways of life, which range from partly underground digging to above-ground to tree-climbing and water-dwelling variants. The greater part of the Kleintenreks inhabit the humid forests of eastern Madagascar, a few species can be found in the drier landscapes of the western part of the island. Various kinship groups can be identified within the genus. The Dunkle Kleintenrek is morphologically and molecularly related to the Cowan Kleintenrek ( Microgale cowani ), but the latter is larger and much more widespread. The genetic difference between the two species is 14.7 to 16.8%, which roughly corresponds to the values in other sister taxa within the Kleintenreks.
The first scientific description of the dark lesser tiger was created in 2006 by Steven M. Goodman and fellow researchers. It is based on twelve individuals from the southwest slope of the Tsaratanana massif in northern Madagascar. All individuals were collected in March 2003. A full-grown female, 12.1 cm long and 10 g, serves as the holotype . It comes from the forests around Lake Matsiborimena about 4 km north of the village of Bemanevika in the province of Mahajanga . The region, which represents the type locality, is 1600 to 1680 m above sea level. The specific epithet jobihely comes from the northern dialect of the Malagasy language , in which joby means something like "dark" or "black" and hely means "small". It thus refers to the appearance and size of the animals.
Threat and protection
The distribution area is relatively small, the species is only known from two clearly separated populations , which are distributed over three sites. The forests of the two northern sites are subject to anthropogenic interference in the form of agricultural use and logging for the production of building materials. A nearby wetland is now being used to grow rice . Both localities are located outside the Tsaratanana National Park , but are enclosed by the Bemanevika Corridor , a non-state reserve. The central-eastern population lives in near-natural but fragmented forests. The area is heavily influenced by mining, but lies within the Ankeniheny-Zahamena Corridor , which is also a non-state protected area. The IUCN lists the Dark Kleintenrek as "critically endangered" ( endangered ).
literature
- Steven M. Goodman, Christopher J. Raxworthy, CP Maminirina, Link E. Olson: A new species of shrew tenrec (Microgale jobihely) from northern Madagascar. In: Journal of Zoology. 270, 2006, pp. 384-398.
- Paulina D. Jenkins: Tenrecidae (Tenrecs and Shrew tenrecs). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 134–172 (p. 172) ISBN 978-84-16728-08-4
Individual evidence
- ↑ a b c d e f g h Steven M. Goodman, Christopher J. Raxworthy, CP Maminirina, Link E. Olson: A new species of shrew tenrec (Microgale jobihely) from northern Madagascar. In: Journal of Zoology. 270, 2006, pp. 384-398.
- ↑ a b c Paulina D. Jenkins: Tenrecidae (Tenrecs and Shrew tenrecs). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 134–172 (p. 172) ISBN 978-84-16728-08-4
- ↑ a b c Voahangy Soarimalala, Martin Raheriarisena, Steven M. Goodman: New distributional records from central-eastern Madagascar and patterns of morphological variation in the endangered shrew tenrec Microgale jobihely (Afrosoricida: Tenrecidae). In: Mammalia. 74, 2010, pp. 187-198.
- ↑ Voahangy Soarimalala, Martin Raheriarisena: The non-volant and non-primate mammals of the Ambatovy Analamay forest. In: Steven M. Goodman, V. Mass (Ed.): Biodiversity, exploration, and conservation of the natural habitats associated with the Ambatovy project. (= Malagasy Nature. 3). 2010, pp. 153-177.
- ^ A b PJ Stephenson, Voahangy Soarimalala, Steven M. Goodman: Microgale jobihely. The IUCN Red List of Threatened Species 2015. e.T136628A4319967 ( [1] ); last accessed on June 28, 2016.
- ↑ a b c Kathryn M. Everson, Voahangy Soarimalala, Steven M. Goodman and Link E. Olson: Multiple loci and complete taxonomic sampling resolve the phylogeny and biogeographic history of tenrecs (Mammalia: Tenrecidae) and reveal higher speciation rates in Madagascar's humid forests . In: Systematic Biology. 65 (5), 2016, pp. 890-909 doi: 10.1093 / sysbio / syw034 .
- ^ JF Eisenberg, Edwin Gould: The Tenrecs: A Study in Mammalian Behavior and Evolution. Smithsonian Institution Press, 1970, pp. 1-138.
- ^ RDE MacPhee: The Shrew Tenrecs of Madagascar: Systematic Revision and Holocene Distribution of Microgale (Tenrecidae, Insectivora). In: American Museum Novitates. 2889. 1987, pp. 1-45.
Web links
- Microgale jobihely in the endangered Red List species the IUCN 2016 Posted by: PJ Stephenson, Voahangy Soarimalala and Steven M. Goodman, 2014. Accessed June 28, 2016th